In the prior art, rear walls of seat backs are produced from what are known as organosheets. Organosheets are thermoplastic panels which are reinforced by endless fibers. Since the organosheet has a thermoplastic matrix, it can be fused and can be encapsulated by injection molding with the same thermoplastic. A distinction is made here between two methods. In the first method, preformed organosheets are inserted into an injection molding die and are encapsulated by injection molding with the thermoplastic. In the second method, the shaping of the organosheet takes place directly in the injection molding die.